Effects of training of operant conditioned reflex on free amino acids in hippocampus of rats

Changes of intracellular levels of free amino acids(FAA) in hippocampus of freely moving rats were measured using intracerebral microdialysis coupled to Orthophthaladehyde (OPA) pre-column derivatization-reversed phase HPLC-f luorescence detection, The analytical method was systematically optimized a nd the real samples were determined. It was employed to analyze the trace l evel of free amino acids(FAA) and possible to qualitative and quantitative 18 kinds of amino acids in every 5 mu L microdialysate. The sensitivity and the linear relation between the amounts and the peak areas were satisfied. The recoveries were 82%-109%, The detection limits reached 0. 5-5. 7 pmol for each FAA. A significant decrease of 14 FAA after training of OCR was fo unded in comparison to basal condition(before training), In fore finds of n eurotransmitter amino acids(NAA), excitatory NAA, glutamic acid and asparti c acid increased 19. 12% and 53. 40% respectively than before training, Inh ibitory NAA, gamma-aminobutyric (GABA), increased 138. 17% than before trai ning. The results confirm that metabolic increase of FAA in hippocampus can be induced by learning and memory in rats, The intracerebral microdialysis technique thus appears to be a useful tool to monitor changes in physiolog ical activity of learning and memory during ongoing behavior.